1NETMASK(1)                       Debian Linux                       NETMASK(1)
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NAME

6       netmask - a netmask generation and conversion program
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SYNOPSIS

9       netmask [ options ] spec [ spec ... ]
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DESCRIPTION

12       This  program  accepts and produces a variety of common network address
13       and netmask formats.  Not only can it convert address and netmask nota‐
14       tions,  but it will optimize the masks to generate the smallest list of
15       rules.  This is very handy if you've  ever  configured  a  firewall  or
16       router  and  some  nasty  network administrator before you decided that
17       base 10 numbers were good places to start and end groups of machines.
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OPTIONS

20       -h, --help
21              Print a summary of the options
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23       -v, --version
24              Print the version number
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26       -d, --debug
27              Print status/progress information
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29       -s, --standard
30              Output address/netmask pairs
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32       -c, --cidr
33              Output CIDR format address lists
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35       -i, --cisco
36              Output Cisco style address lists
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38       -r, --range
39              Output ip address ranges
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41       -x, --hex
42              Output address/netmask pairs in hex
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44       -o, --octal
45              Output address/netmask pairs in octal
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47       -b, --binary
48              Output address/netmask pairs in binary
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50       -n, --nodns
51              Disable DNS lookups for addresses
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DEFINITIONS

54       A spec is an address specification, it can look like:
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56       address
57              One address.
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59       address1:address2
60              All addresses from address1 to address2.
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62       address1:+address2
63              All addresses from address1 to address1+address2.
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65       address/mask
66              A group starting at address spanning mask.
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68       An address is an internet network address, it can look like:
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70       ftp.gnu.org
71              An internet hostname.
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73       209.81.8.252
74              A standard dotted quad internet address notation.
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76       100    A decimal number (100 in this case).
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78       0100   An octal number preceded by "0" (64 in this case).
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80       0x100  A hexadecimal number preceded by "0x" (256 in this case).
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82       A mask is a network mask, it can look like:
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84       255.255.224.0
85              A dotted quad netmask (netmask will complain  if  it  is  not  a
86              valid netmask).
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88       0.0.31.255
89              A Cisco style inverse netmask (with the same checks).
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91       8      The number of bits set to one from the left (CIDR notation).
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93       010    The number of bits set to one from the left in octal.
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95       0x10   The number of bits set to one from the left in hexadecimal.
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AUTHOR

98       netmask  was  written by Robert Stone.  Some algorithm design and opti‐
99       mization was provided by Tom Lear.  This manual  page  was  written  by
100       Robert Stone.
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BUGS

103       Let  me  know  if you find any.  This man page is a bit more simplistic
104       than I'd like, but I've forgotten most of the groff I once knew.
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SEE ALSO

107       ipchains(1), ipfwadm(8),  netstat(8),  route(8),  routed(8),  gated(8),
108       tcpd(8)
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112Debian Project                    15 May 1999                       NETMASK(1)